1. Field
Invention relates generally to the field of medicine and more specifically to a device and method for rapid extraction of tissue from an enclosed body cavity.
2. Related Art
Bone Marrow is a rich source of pluripotent hematopoietic stem cells from which red blood cells, white blood cells, and platelets are formed. Bone marrow also contains additional populations of cells which have the potential to regenerate other tissues.
Since the early 1970's bone marrow and hematopoietic stem cell transplantation has been used to treat patients with a wide variety of disorders, including but not limited to cancer, genetic and autoimmune diseases. Currently over 400,000 transplants for a variety of indications are performed worldwide each year.
In autologous transplants, the patient has their own bone marrow collected prior to receiving high dose chemotherapy. Following high dose, myeloablative chemotherapy (which kills the majority of the patients marrow stem cells) the stored autologous marrow (or hematopoietic stem cells purified or enriched from the marrow) is infused, and serves to ‘rescue’ the patient's hematolymphoid system.
In allogeneic transplants bone marrow, or other sources of hematopoietic stem cells derived from a full or partially human leukocyte antigen (HLA) matched sibling, parent or unrelated donor is infused into the recipient patient and following engraftment, serves to reconstitute the recipients hematopoietic system with cells derived from the donor.
Following myeloablative or non-myeloablative conditioning of a patient with chemotherapy and/or radiation therapy, the marrow is regenerated through the administration and engraftment of hematopoietic stem cells contained in the donor bone marrow.
In addition to hematopoietic stem cells and hematopoietic progenitors, bone marrow contains mesenchymal and other stem cell populations thought to have the ability to differentiate into muscle, myocardium, vasculature and neural tissues and possibly some organ tissues such as liver and pancreas. Recent research in preclinical animal studies (for example Rafii S, et al., Contribution of marrow-derived progenitors to vascular and cardiac regeneration, Semin Cell Dev Biol 2002 February; 13(1):61-7) and clinical trials (for example of recent clinical trials and methods see Strauer B E, Wernet P. et al. Repair of infracted myocardium by autologous intracoronary mononuclear bone marrow cell transplantation in humans. Circulation 2002 Oct. 8; 106(15):1913-8, and the article by Stamm C, et al. Autologous bone-marrow stem-cell transplantation for myocardial regeneration. Lancet 2003 Jan. 4; 361 (9351):45-6) suggest that bone marrow or some portion of the cells contained within marrow can regenerate tissues other than the hematopoietic system. This includes the ability for cells contained within the marrow to regenerate or facilitate regeneration of myocardial tissue following a myocardial infarction, as evident by improved cardiac function and patient survival (Strauer B E, et al. Intracoronary, human autologous stem cell transplantation for myocardial regeneration following myocardial infarction, Dtsch Med Wochenschr 2001 Aug. 24; 126(34-35):932-8).
Bone marrow derived stem cells also show evidence for their ability to regenerate damaged liver and hepatic cells (Lagasse E et al Purified hematopoietic stem cells can differentiate into hepatocytes in vivo, Nature Medicine 2000 November; 6(11):1229-34) and portions of the nervous system (Cuevas P et al. Peripheral nerve regeneration by bone marrow stromal cells, Neurol Res 2002 October; 24(7):634-8 Arthritis Res Ther 2003; 5(1):32A5) including spinal cord (Wu S et al Bone marrow stromal cells enhance differentiation of cocultured neurosphere cells and promote regeneration of injured spinal cord. J Neurosci Res 2003 May 1; 72(3):343-51.). Additional organ systems including kidney show benefit from bone marrow derived cells (Poulsom R et al. Bone marrow stem cells contribute to healing of the kidney, J Am Soc Nephrol 2003 June; 14 (Suppl 1):S48-54). Use of bone marrow and the stem cells contained within bone marrow may be of increasing clinical utility in the future treatment of patients.
Stem cells utilized in transplantation are primarily collected in one of two ways. First, by directly accessing the bone marrow (bone marrow harvest), in which marrow is removed from the patient, usually by multiple aspirations of marrow from the posterior ileac crest, in a bone marrow harvest procedure performed in the operating room. A second collection method is performed by removal of mononuclear cells from the donor's peripheral blood (which contains a fraction of hematopoietic stem cells as well as other populations of cells including high numbers of T-cells. In this procedure peripheral blood stem cells are collected by apheresis following donor treatment with either chemotherapy (usually cyclophosphamide) or with the cytokine Granulocyte Colony Stimulating Factor (GCSF). Treatment with cyclophosphamide or GCSF functions to mobilize and increase the numbers of hematopoietic stem cells circulating in the blood.
Traditional bone marrow harvest procedures have several shortcomings:                To perform a harvest of 500-1000 milliliters of marrow, multiple separate entries into the marrow cavity are required to in order to remove a sufficient amount of bone marrow. A bone marrow aspiration needle (sharp metal trocar) is placed through the soft tissue, through the outer cortex of the ileac crest and into the marrow space. The aspiration needle enters less than 2 cm into the marrow cavity. Negative pressure is applied through the hollow harvest needle (usually by the operator pulling on an attached syringe into which 5-10 ml of marrow is aspirated). The needle and syringe are then removed and after removing the collected marrow, the aspiration needle accesses a separate location on the ileac bone for another aspiration. This is performed multiple times (on the order of 100-200 separate entries for an average patient) in order to remove a sufficient volume of bone marrow required for transplantation. Each puncture and entry into the marrow cavity accesses only a limited area of the marrow space, and the majority of practitioners only remove 5-10 milliliters of marrow with each marrow penetration. Pulling more marrow from a single marrow entry site otherwise results in a collected sample highly diluted by peripheral blood.        General anesthesia—The bone marrow harvest procedure requires general anesthesia. General anesthesia is required because the ileac crest is penetrated 100-300 times with a sharp bone marrow trocar. Local anesthesia is generally not possible given the large surface area and number of bone punctures required.        Recovery Time—The donor can take some time recovering from general anesthesia, and frequently suffers from days of sore throat, a result of the endotracheal intubation tube placed in the operating room.        Time consuming for patient—Pre-operative preparation, the harvest procedure, recovery from anesthesia, and an overnight observation stay in the hospital following the procedure is an imposition on the donor.        Time Consuming for the physician: In addition to general operating room staff, the traditional bone marrow harvest procedure requires two transplant physicians (each physician aspirating marrow from the left or right side of the ileac crest) and. Who spend approximately one hour each to perform the procedure.        Pain—Many donors experience significant pain at the site of the multiple aspirations (bone punctures) which persists for days to weeks.        Complications—Traditional bone marrow aspiration incurs a significant degree of contamination with peripheral blood. Peripheral blood contains high numbers of mature T-cells (unlike pure bone marrow). T-cells contribute to the clinical phenomenon termed Graft vs. Host Disease (GVHD), in both acute and chronic forms following transplant in which donor T-cells present in the transplant graft react against the recipient (host) tissues. GVHD incurs a high degree of morbidity and mortality in allogeneic transplants recipients.        Expensive—Cost of the procedure $10-15K, which includes costs for operating room time, anesthesia supplies and professional fees, and post-operative care and recovery.        
Peripheral Blood Stem Cell Collection also has several shortcomings:                Slow and time consuming—Requires the donor to first undergo 7-10 or more days of daily subcutaneous injections with high doses of the cytokine GCSF prior to the harvest. These daily injections can be uncomfortable and painful. Peripheral blood stem cells can not be obtained without this 7+ day lead time.        Expense—Each day of apheresis costs approximately $3000 (including but not limited to the cost of the apheresis machine, nursing, disposable supplies and product processing) and the patient often has to come back on multiple days in order to obtain an adequate number of stem cells. Costs for the GCSF drug alone approximate $6,000-10,000 depending upon the weight of the patient (usually doses as 10 micrograms/kilogram/day).        Complications—Given the multiple days required to collect adequate numbers of hematopoietic stem cells, individual bags of peripheral blood product must processed and frozen separately. These bags are then thawed, and given back to the recipient patient at the time of transplant. The volume, and chemicals contained in the product freezing media can cause some mild side effects at the time of infusion.        
Accordingly, there is a need for a minimally invasive, less expensive, time-efficient bone marrow harvest procedure with minimal complications which does not require general anesthesia, offers fast recovery time, and does not cause significant pain to the bone marrow donor.